How To Get Rid Of Lichens, Start A Garden On Your Deck
WSU/King County Cooperative Extension
Q: How do I get rid of lichens on my fruit trees?
A: Lichens are rather fascinating things. Within the lichen a fungus and an alga live together so closely that they appear to be one plant. They grow abundantly on twigs and trunks of many trees and shrubs. Many look like crusty growths, some appear more leaf-like and others hang in long, thread-like festoons from the trees. Typically they are colored gray, white, yellow or greenish.
Lichens have chlorophyll and manufacture their own food, so they are not parasitic on the host plant. They could as easily growon a rock and do no harm to your fruit tree.
When lichens are thick, gardeners often fear they are suffocating the plant. This doesn't happen, but lichens may interfere a bit with bud development. A healthy, vigorous plant easily overcomes the lichen. Proper fertilization, watering and cultural management of the fruit trees will assure their health despite the presence of lichens.
The choice to control lichens is usually made for aesthetic reasons. Some people think they are unsightly, although others like the color and interest they add.
Several fungicides used as a dormant spray will control lichens. Copper fungicides (such as Microcop) and lime sulfur are the most acceptable for gardeners trying to follow organic gardening practices. Make sure the kind of plant you want to spray is on the pesticide's label and then carefully follow the directions for dormant-season disease control.
The buds on fruit trees are already expanding, so you should probably wait until next winter to spray. A single spray should kill the lichens, but remember that it won't make them magically disappear. Weathering and plant growth will cause them to flake off over time.
Q: I have a nice-sized deck outside my apartment. How do I best use it to plant a garden?
A: If yours is a ground-level deck, you can create your own mini Garden of Eden. If your space is actually a balcony, you will need to approach this project with caution. Look around at what is on other decks in your building and estimate how much weight they can support. Or, consult your landlord. Large containers of wet soil are incredibly heavy.
You can use any kind of container. Clay will need to be watered more frequently; wood has a nice look and lasts several years; plastic is very durable and is the lightest material. All containers should have drainage holes, so you must use trays, saucers or consider where runoff will go.
Containers need a depth of at least 6 inches, but 8-10 would be even better. If you have a deeper container, such as a half whiskey barrel, you may want to put a few inches of styrofoam packing "peanuts" in the bottom to keep things lighter. (Cover the styrofoam layer with cloth or newspaper, so they don't float up into the soil.)
Fill your containers with a good packaged soil mix containing lots of compost or peat and perlite or vermiculite. Regular garden soil usually contains too much clay to work well in containers.
What you choose to grow will be up to you and your deck's exposure. If it gets more than six hours of sun a day, you can grow most anything. North and east-facing decks are more limited. In a low-light situation try leafy crops such as lettuce, spinach, chard, mustards, choys, collards, etc. If they work, try root crops like radishes, beets, carrots, turnips, etc. Fruiting crops like tomatoes, peppers and eggplants need lots of sun.
If you want to grow flowers, impatiens, fuchsias and begonias are perfect choices for semi-shaded decks. Geraniums and petunias are favorites for sunny decks.
Some people don't care about veggies or flowers. They want something nice looking year 'round. In this case, a dwarf conifer surrounded by a variegated ivy or other groundcover might be the answer. Leave room for a few marigolds or other annuals for summer
and pansies for winter.
Gardening runs Friday in Scene and Sunday in Home/Real Estate. It is prepared by Mary Robson, Master Gardener program director, Holly Kennell, WSU/King County Cooperative Extension agent, Susan Miller, integrated pest management specialist, and volunteer Master Gardeners.
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